I am stumped by these two tools that where salvaged from a scrap bin and despite searching I can't find anything so I am now trying here.
Number 1 has the markings ZG+38 and under that 2830B on the "front plate". when you press in the stop bar that protrudes forward the front plate pivots to an angle (I have shown this in one of the pics) I am assuming a round cutter is mounted on the front plate and the best guess I have is that it could put a undercut inside a bore.